Prefetch command control method, prefetch command control apparatus and cache memory control apparatus

Abstract

A prefetch command control apparatus is provided. A protocol slot generation unit, when receiving from a CPU a prefetch command in which a utilization time of data to be prefetched is specified, generates a protocol slot based on the utilization time and registers it in a schedule list storage unit. When receiving a regular access command, the protocol slot generation unit registers a protocol slot in a regular protocol queue storage unit. A cost evaluation unit evaluates an issuance cost of the prefetch command based on a cache retention time of data to be prefetched and evaluates an issuance cost of the regular access command based on a resource occupation cost. A protocol issuance unit decides which command shall be issued, the prefetch command or regular access command, based on the evaluation result of these issuance costs.

1. A tangible storage medium storing a computer program executable by a computer, the computer program comprising:
 analyzing a source code and converting the source code into an intermediate code; 
 determining data to be prefetched based on the intermediate code, and then inserting an access command for the data as a prefetch command into a position before an original execution sequence position, and adding information specifying a utilization time of the data in the prefetch command; and 
 optimizing the intermediate code into which the prefetch command is inserted and generating an object code. 
 
   
   
     2. The tangible storage medium of  claim 1 , wherein the information specifying the utilization time includes information specifying a utilization start time of the data to be prefetched, which is defined by a relative position from a position where the prefetch command is inserted. 
   
   
     3. The tangible storage medium of  claim 2 , wherein the information specifying the utilization time further includes information specifying a utilization finish time of the data to be prefetched, which is defined by a relative position from a position where the prefetch command is inserted. 
   
   
     4. A method for generating an object code comprising:
 analyzing a source code and converting the source code into an intermediate code; 
 determining data to be prefetched based on the intermediate code, and then inserting an access command for the data as a prefetch command into a position before an original execution sequence position, and adding information specifying a utilization time of the data in the prefetch command; and 
 optimizing the intermediate code into which the prefetch command is inserted and generating the object code. 
 
   
   
     5. A computer readable media storing an object code generated by the method of  claim 4 . 
   
   
     6. The method of  claim 4 , wherein the information specifying the utilization time includes information specifying a utilization start time of the data to be prefetched, which is defined by a relative position from a position where the prefetch command is inserted. 
   
   
     7. A computer readable media storing an object code generated by the method of  claim 6 . 
   
   
     8. The method of  claim 6 , wherein the information specifying the utilization time further includes information specifying a utilization finish time of the data to be prefetched, which is defined by a relative position from a position where the prefetch command is inserted. 
   
   
     9. A computer readable media storing an object code generated by the method of  claim 8 .